- Fix write_device_impl<ostream_tag>. Fixes #3839
- Fix error checks after calling SetFilePointer. Fixes #3953
- Gzip filter shouldn't require its source to be peekable. Fixes #3723.
- In `position_to_offset`, only cast to `stream_offset` after calculating
`_Myoff`. Fixes #3969.
- ptrdiff_t is in std. Fixes #2505.
[SVN r60666]
Daniel James